Calculations of interfacial interactions in pyrene-Ipa rod sensitizednanostructured TiO_2

摘要

Pyrene chromophores carrying different rigid rod spacer groups (ethynylene,ethynylene-phenylene-ethynylene, and ethynylene-bicyclo[2.2.2]octylene-ethynylene) and bound to Ti02nanostructured materials via an isophthalic acid (Ipa) anchor group have been investigated usingquantum chemical calculations in order to elucidate structural and electronic properties ofdye-sensitized semiconductor structures capable of long-range photoinduced interfacial electrontransfer. The calculations are used to study firstly the effect of the anchor and spacer groups on theelectronic properties of the pyrene-dyes, secondly the binding of isophthalic acid to nanostructuredTi02, and thirdly the interfacial electronic interactions for dye-sensitized nanostructured Ti02 relevantto dye-sensitized solar cell applications. Together, these calculations provide theoretical insights into theeffect of incorporating rigid rod anchor-cum-spacer group motifs in sensitizers for e.g. solar cellapplications. In particular, the calculations help to rationalize the strong influence of the rods on thephotophysical properties of the sensitizers in terms of electronic interactions between the individualchromophore, spacer, and anchor segments, as well as to provide information about interfacialelectronic interactions of interest for the capabilities of the rods to act as efficient mediators ofphotoinduced interfacial charge separation.